The importance of languages in the UDC is consistent with the significance of linguistic facets for knowledge organization in general. Languages are the main facet category implicated in processes as crucial as the development of the Linguistics class, the organization of national and regional literatures, the categorization of human ancestries, ethnic groupings and nationalities, and the description of the language in which a document is written. Language numbers are extensively used across the entire UDC scheme, and form the basis for a faceted approach in class structuring and number building. For this reason, Common Auxiliaries of Languages (Table 1c) deserve special attention.
Upon the completion of the revision of American indigenous languages (2007-2008), it was evident that other language families would benefit from the same careful examination. The next class we are looking to improve is =4, Afro-Asiatic, Nilo-Saharan, Congo-Kordofanian, Khoisan languages. Thus, in 2009 the author has started a research into indigenous languages of Africa. In this paper, the initial research findings for the improvement of the class =4 are presented.

The importance of languages in the UDC is consistent with the significance of linguistic facets for knowledge organization in general. Languages are the main facet category implicated in processes as crucial as the development of the Linguistics class, the organization of national and regional literatures, the categorization of human ancestries, ethnic groupings and nationalities, and the description of the language in which a document is written. Language numbers are extensively used across the entire UDC scheme, and form the basis for a faceted approach in class structuring and number building. For this reason, Common Auxiliaries of Languages (Table 1c) deserve special attention.
Upon the completion of the revision of American indigenous languages (2007-2008), it was evident that other language families would benefit from the same careful examination. The next class we are looking to improve is =4, Afro-Asiatic, Nilo-Saharan, Congo-Kordofanian, Khoisan languages. Thus, in 2009 the author has started a research into indigenous languages of Africa. In this paper, the initial research findings for the improvement of the class =4 are presented.